The U.S. Defense Advanced Research Projects Agency (DARPA) has revealed more details about the future aircraft under the SPeed and Runway INdependent Technologies (SPRINT) program to replace V-22 Osprey. It has received the designation X-76.
The name was reportedly chosen in honor of the 250th anniversary of U.S. independence, declared in 1776. It was also announced that flight tests are envisioned in the third development phase, which should begin in early 2028.
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The second development phase is currently ongoing, during which prototype construction is being conducted and ground tests are planned. Bell company is responsible for the work, having successfully passed critical design review (CDR), featuring unique jet engines with large-diameter blades.
Recall that the SPRINT project envisions creating a vertical takeoff and landing aircraft. It should conceptually replace V-22 Osprey tiltrotors, which became notorious for reliability problems.
Requirements include capability to reach speeds over 740 km/h, hovering in severe conditions, and operation from unprepared airfields. This will enable rapid transport of military personnel and equipment from locations where conventional aircraft are difficult to use. Island hopping in the Pacific Ocean can be cited as an example.
As a result, DARPA selected Bell's proposal, which envisioned a tiltrotor with unique HSVTOL (High-Speed Vertical Take-Off and Landing) engines. Corresponding work has been ongoing for over 5 years, with developments patented back in December 2020.
According to the project, takeoff, landing and hovering are accomplished through rotors, as on a tiltrotor. After transitioning to horizontal flight and reaching corresponding speed, the blades fold and the aircraft then flies using jet thrust.
The unique engines already underwent testing in summer 2025, so the 2028 flight start timeline sounds realistic. At the same time, the question of tiltrotor reliability remains important, given V-22 Osprey problems.
At the same time, for Black Hawk helicopter replacement, the U.S. selected another tiltrotor V-280 Valor or MV-75 from the same Bell company. Perhaps they will now succeed in improving such equipment reliability, especially if it will occupy two important niches simultaneously in the American military.
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